The treatment of trees and other woody vegetation has, in the past, been done via airborne broadcast exposure of a treating compound to the vegetation to be treated. Recently, however, increasing environmental constraints have limited broadcast application and, as such, new methods and devices for treating trees have evolved out of necessity. Typically the use of capsules pre-charged with an chemical injectant for driving into a tree with a lance device have been developed in the art. Generally, the use of a lance device has been proposed to drive the capsules into trees since its use affords an economical, environmentally friendly and efficient manner to chemically treat the vascular system of a tree.
An example of a known lance used for this purpose is disclosed by Dillistone in Canadian Patent No. 1,191,346. The device employs an open slidably mounted loading mechanism for loading a capsule into contact with a driving member. The capsule must drop by gravity into a channel for engagement with the driving member. As such, the loading mechanism is highly susceptible to jamming and other mechanical limitations which require extensive disassembly in the field to repair. Further, due the exposure of the loading mechanism, branches and other debris enter the mechanism during use, eventually rendering it inoperative.
Various other lance devices are known in the art such as those disclosed in U.S. Pat. Nos. 2,795,899, 2,796,791, 2,290,363 and 3,290,822. Many of these devices employ a superfluous amount of parts, all of which are susceptible to mechanical failure and further are not well adapted for reliable use in the field.
From a consideration of the relevant art, one can clearly see that there is a need for a lightweight mechanically efficient lance which traverses the limitations of the prior art devices. To this end, Applicant with the present invention, addresses this need by providing a lance which is simple in construction, incorporating the least possible number of components, and further which is highly dependable during use.